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<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    
</body>
<script>
    //创建函数 生成当前时间的字符串
    /**
     * 格式2021-10-19 10:17:20
     * 作为函数的返回值返回
    */
   function identify(num){
       return num < 10?"0"+num:num;
   }
   function showTime(){
       var now = new Date();
       var year = now.getFullYear();
       var month = now.getMonth() + 1;
       var date = now.getDate();
       var hour = now.getHours();
       var minute = now.getMinutes();
       var second = now.getSeconds();
       month = identify(month);
       date = identify(date);
       hour = identify(hour);
       minute = identify(minute);
       second = identify(second);
       var result = year+"-"+month+"-"+date+"  "+hour+":"+minute+":"+second;
       return result;
    }
    document.write(showTime()+"<br/>");
    document.write((new Date).toLocaleString());
</script>
</html>